1. Field of the Invention
The present invention relates to a seat apparatus for use in a vehicle seat. More specifically, the invention relates to a seat apparatus which enables an operation of releasing a reclining lock of a seat back (back rest) and an operation of resetting (raising) the reclined seat back after the release of the reclining lock by remote control from a location away from the seat.
2. Description of the Related Art
With the spread of an electric power-assist vehicle seat, there have been provided various seat apparatuses which enable the operation of releasing the reclining lock of the seat back and the operation of raising the reclined seat back by remote control. For example, according to a seat actuator disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. 2006-290334, the actuator is coupled to a reclining lock releasing lever (22) of the vehicle seat with a control cable (14) for the reclining lock releasing operation, and the actuator is couple to a seat back raising lever (21) of the vehicle seat with a control cable (15) for the seat back raising operation. The seat actuator includes a single motor (M), relay gears (2, 3) to which a rotational driving force of the motor is transmitted, and a first one-way clutch (4) and a second one-way clutch (8) to which rotations of the relay gears are transmitted.
The first one-way clutch (4) is operationally coupled to the control cable (14) for the reclining lock releasing operation through a first cam-crank mechanism. The second one-way clutch (8) is operationally coupled to the control cable (15) for the seat back raising operation through a second cam-crank mechanism. These two one-way clutches (4, 8) have conflicting power transmission characteristic with respect to rotation of the relay gear, and according to the rotational direction of the relay gears, only one of the two one-way clutches can transmit power to the corresponding cam-crank mechanism. That is, upon rotation of the motor (M) in the normal direction, only the first one-way clutch (4) is activated and the lever (22) is pulled through the control cable (14), thereby releasing the reclining lock. Upon rotation of the motor (M) in the reverse direction, on the contrary, only the second one-way clutch (8) is activated and the lever (21) is pulled through the control cable (15), thereby raising the seat back. As described above, the seat actuator disclosed in JP-A-2006-290334 can selectively perform the seat back reclining lock releasing operation and the seat back raising operation by use of one motor.
The technique disclosed in JP-A-2006-290334 attempts to reduce the seat actuator in size by combining the relay gears of relatively small diameter with the two one-way clutches. However, the use of a plurality of one-way clutches necessarily leads to complicated mechanical configuration and miniaturization of the actuator is limited. Moreover, since the seat back raising operation is performed through the control cable, a sufficiently strong motor is required and thus, miniaturization of such motor is difficult.